Polymetallic iron ore sulphate deposits of marine volcanic rock have been developed in the Fangniugou area,Jilin Province,China,but the division of volcanic ore-bearing strata has not been specifically elucidated and ...Polymetallic iron ore sulphate deposits of marine volcanic rock have been developed in the Fangniugou area,Jilin Province,China,but the division of volcanic ore-bearing strata has not been specifically elucidated and there is disagreement about the division.The sampling and SHRIMP U-Pb zircon dating of volcanic rock for Daheishan in the Fangniugou area and the northeast slope of the Duanjiadian were described.The volcanic rock formation period and recorded the volcanic events in the Daheishan mountains were systematically researched.Two samples of high-precision U-Pb zircon dating were used to represent the volcanic rock fomation period of the Late Silurian.The measured data reflect that multiple volcanic activities occurred during the Middle Silurian,Early Silurian,Middle Ordovician and Silurian,and Late Ordovician,probably matching volcanic events in the Songnan Basin identified from zircon dating.At the same time,it is confirmed that a controversial "conglomerate of Daheishan" did in fact develop in the Late Silurian,and those sections of both the Dazigou and Xinlitun-Taoshan with graptolite had been reversed.展开更多
Titanite(CaTi2SiO5) is an important accessory mineral not only in magmatic and metamorphic rocks,but also commonly in hydrothermal mineral deposits. It incorporates appreciable amounts(usually 10×10-6 s to 100&#...Titanite(CaTi2SiO5) is an important accessory mineral not only in magmatic and metamorphic rocks,but also commonly in hydrothermal mineral deposits. It incorporates appreciable amounts(usually 10×10-6 s to 100×10-6 s) of U and Th into its structure and has a closure temperature of Pb diffusion higher than 660～700 ℃(Scott and St-Onge,1995) ,making it an ideal U-Th-Pb geochronometer. The Daye metallogenic district is located in the west of the giant Middle-Lower Yangtze River(MLYR) Cu-Fe-Au province,eastern China and is well endowed with Fe,Cu,and polymetallic skarn deposits.展开更多
The Shiyaogou deposit,located in Songxian,Henan Province,China,is a medium-sized Molybdenum deposit newly discovered in the East Qinling molybdenum belt.Occurring in the altered Proterozoic Xionger Group,mineralizatio...The Shiyaogou deposit,located in Songxian,Henan Province,China,is a medium-sized Molybdenum deposit newly discovered in the East Qinling molybdenum belt.Occurring in the altered Proterozoic Xionger Group,mineralization of the deposit consists of molybedenite disseminations and quartz -molybdenite veinlets and stockworks.Hydrothermal alteration is well developed and is composed of potassic alteration,silicification,sericitization,pyriti-展开更多
The detailed geochemical research indicates that the tholeiitic basalts from Ganlongtang-Longba ophiolitic m（?）lange exhibit distinctive geochemical characteristics of high TiO<sub>2</sub> and low K<s...The detailed geochemical research indicates that the tholeiitic basalts from Ganlongtang-Longba ophiolitic m（?）lange exhibit distinctive geochemical characteristics of high TiO<sub>2</sub> and low K<sub>2</sub>O,and depletion of light rare earth elements.They should be originated from a depleted asthenosphere mantle, belonging to ancient oceanic crust ophiolitic volcanic rock association.Compared with the Longba tholeiitic basalt,the Ganlongtang tholeiitic basalt shows展开更多
Vast thickness gravel formation developed widely around Tibetan Plateau, it provides the evidences of the uplift strongly process of Tibetan Plateau and it is also the products of uplift. So the study on origin, sedim...Vast thickness gravel formation developed widely around Tibetan Plateau, it provides the evidences of the uplift strongly process of Tibetan Plateau and it is also the products of uplift. So the study on origin, sediment environment and deposit faces of gravel layers can reveal the process and feature of Tibetan Plateau. According texture and components and glue degree and lithostratigraphy context of gravels, these gravel layers were divided into lower Pleistocene Yumen gravel formation and Middle Pleistocene Jiuquan gravel formation by Prof. Sun Jianchu in 1942. Since then, a lot of works have been carried including magnetic chronology. However, the absolute accumulated age of gravel is not yet identical because of different methods and precision. In this paper, a 1000m thick Cenozoic sediment at Laojunmiao, located at the northern foothill of Qilian Mt., is dating for ESR systematically. 19 block samples were collected for ESR dating. The pretreated samples were irradiated with a 60 Co\|source in different dosage. The irradiated samples were kept untouched for about ten days and then measured with a JES\|FEIXG ESR spectrum with the following measurement conditions: room temperature, X\|band, Microwave power: 0 1mW and 2mW, modulation amplitude: 0 8mT, magnetic field scanning range (334±5)mT. We select Ge and E’ centre as the dating signal. The concentrations of radioactive elements, U, Th, K 2O, were determined by laser fluorescence, colorimetric spectrophotometry and atomic absorption techniques, respectively. AD value were obtained by linear regression. The results show that it is linear relationship between age and depth (thickness), and the age is well identical with paleomagnetic age.展开更多
Recently the (U\|Th)/He method on apatite has been applied to studies of cooling and exhumation in mountain belts in order to place constraints on the low temperature cooling history (Wolf et al., 1997; House et al., ...Recently the (U\|Th)/He method on apatite has been applied to studies of cooling and exhumation in mountain belts in order to place constraints on the low temperature cooling history (Wolf et al., 1997; House et al., 1998). Because the closure temperature of the method is 65～75℃, it provides useful information regarding the exhumation of rocks through the upper few kilometers of the earth’s crust. When the (U\|Th)/He method is coupled with methods such as 40 Ar/ 39 Ar with higher closure temperatures (210～500℃), a cooling history can be reconstructed over a wide range of temperatures. In eastern Nepal, in the Dudh Kosi valley a suite of samples from the Main Central Thrust (MCT) to the middle of the Higher Himalayan section was previously dated using 40 Ar/ 39 Ar on K\|feldspar, biotite, muscovite, and hornblende (Hubbard and Harrison,1989). We have applied the (U\|Th)/He method to apatite from these same samples. The structurally highest site, Ngozumba, is in the middle to upper part of the Higher Himalaya in the Gokyo valley. At Ngozumba previous 40 Ar/ 39 Ar ages include: muscovite at (16 6±0 4)Ma (closure temperature (CT)350℃), biotite at (16 8±1 4)Ma (CT 300℃), and K\|feldspar at (15 5±1 8)Ma (CT 250℃).The apatite age for an augen gneiss from this location was (6 3±3 8)Ma suggesting slower cooling for that part of the range during the last 15Ma. Structurally below Ngozumba, in the MCT zone, 40 Ar/ 39 Ar ages include:(20 9±0 2)Ma for hornblende (CT 500℃), (12 0±0 2)Ma for muscovite, and (8 0±0 2)Ma for K\|feldspar (CT 220℃). The apatite age obtained for a biotite schist at this location was (4 6±0 2)Ma and is consistent with relatively constant cooling since 12Ma. In between the MCT and the Ngozumba site samples were collected near the settlement of Ghat that yielded anomalously young 40 Ar/ 39 Ar ages:(7 7±0 4)Ma for muscovite, (7 5±0 6)Ma for biotite, and (3 6±0 2)Ma for K\|feldspar (CT 210℃). The apatite age is consistent with these young ages at (0 8±0 1)Ma. Plausible explanations for the young ages at this site include: post\|MCT age movement on a small\|scale shear zone or late\|stage movement of hydro\|thermal fluids through this localized zone. The MCT zone 40 Ar/ 39 Ar ages were used to constrain a one\|dimensional thermal model aimed at understanding rates of exhumation (Hubbard et al., 1991). The model yielded exhumation rates of 0 7～1 9km/Ma for the MCT zone region. The (U\|Th)/He age for apatite from this region is consistent with the model results. By coupling the (U\|Th)/He ages with the 40 Ar/ 39 Ar ages in this region we can determine that exhumation processes have acted at a relatively constant rate during the last 15～20 million years (with the possible exception of the Ghat location). Major fault activity likely pre\|dates this time period, or has had little affect on the cooling history.展开更多
The journal Chemical Research in Chinese Universities is a comprehensive academic journal in the field of chemistry,published bimonthly since 1984.The journal publishes research articles,letters/communications and rev...The journal Chemical Research in Chinese Universities is a comprehensive academic journal in the field of chemistry,published bimonthly since 1984.The journal publishes research articles,letters/communications and reviews written by faculty members,researchers and postgraduates in universities,colleges and research institutes all over China and overseas.It reports the latest and the most creative results of important fundamental research in all aspects of chemistry and of developments with significant consequences across sub-disciplines.This journal is sponsored by Jilin University and mandated by the Ministry of Education of P.R.China.展开更多
The journal Chemical Research in Chinese Universities is a comprehensive academic journal in the field of chemistry,published bimonthly since 1984.The journal publishes research articles,letters/communications and rev...The journal Chemical Research in Chinese Universities is a comprehensive academic journal in the field of chemistry,published bimonthly since 1984.The journal publishes research articles,letters/communications and reviews written by faculty members,researchers and postgraduates in universities,colleges and research institutes all over China and overseas.It reports the latest and the most creative results of important fundamental research in all aspects of chemistry and of developments with significant consequences across sub-disciplines.This journal is sponsored by Jilin University and mandated by the Ministry of Education of P.R.China.展开更多
The journal Chemical Research in Chinese Universities is a comprehensive academic journal in the field of chemistry,published bimonthly since 1984.The journal publishes research articles,letters/communications and rev...The journal Chemical Research in Chinese Universities is a comprehensive academic journal in the field of chemistry,published bimonthly since 1984.The journal publishes research articles,letters/communications and reviews written by faculty members,researchers and postgraduates in universities,colleges and research institutes all over China and overseas.It reports the latest and the most creative results of important fundamental research in all aspects of chemistry and of developments with significant consequences across sub-disciplines.This journal is sponsored by Jilin University and mandated by the Ministry of Education of P.R.China.展开更多
A method for age dating of uranium mineral particles by double focusing magnetic sector inductively coupled mass spectrometry (FS-ICPMS) and thermal ionization mass spectrometry (TIMS) was presented. Pb/U ratio in ura...A method for age dating of uranium mineral particles by double focusing magnetic sector inductively coupled mass spectrometry (FS-ICPMS) and thermal ionization mass spectrometry (TIMS) was presented. Pb/U ratio in uranium mineral particles was measured by FS-ICPMS without any chemical separation procedure. Pb isotope composition in uranium mineral particles was determined by TIMS associated with micro column anion exchange resin method. Due to simplified chemical procedure and minimum use of reagents, the full procedure blank was reduced to 230 pg Pb, leading to the successful age dating of uranium mineral particles with relative standard deviation less than 2%.展开更多
基金Project(2009GYXQ02-06) supported by the National Oil and Gas Resources of Strategic Project Selection Survey and Evaluation Fund from Land and Natural Resources Ministry,ChinaProject(2652013099) supported by the Fundamental Research Funds of Central Universities,China
文摘Polymetallic iron ore sulphate deposits of marine volcanic rock have been developed in the Fangniugou area,Jilin Province,China,but the division of volcanic ore-bearing strata has not been specifically elucidated and there is disagreement about the division.The sampling and SHRIMP U-Pb zircon dating of volcanic rock for Daheishan in the Fangniugou area and the northeast slope of the Duanjiadian were described.The volcanic rock formation period and recorded the volcanic events in the Daheishan mountains were systematically researched.Two samples of high-precision U-Pb zircon dating were used to represent the volcanic rock fomation period of the Late Silurian.The measured data reflect that multiple volcanic activities occurred during the Middle Silurian,Early Silurian,Middle Ordovician and Silurian,and Late Ordovician,probably matching volcanic events in the Songnan Basin identified from zircon dating.At the same time,it is confirmed that a controversial "conglomerate of Daheishan" did in fact develop in the Late Silurian,and those sections of both the Dazigou and Xinlitun-Taoshan with graptolite had been reversed.
基金supported by the NSFC(Grants Nos.90814004 and 40821061)
文摘Titanite(CaTi2SiO5) is an important accessory mineral not only in magmatic and metamorphic rocks,but also commonly in hydrothermal mineral deposits. It incorporates appreciable amounts(usually 10×10-6 s to 100×10-6 s) of U and Th into its structure and has a closure temperature of Pb diffusion higher than 660～700 ℃(Scott and St-Onge,1995) ,making it an ideal U-Th-Pb geochronometer. The Daye metallogenic district is located in the west of the giant Middle-Lower Yangtze River(MLYR) Cu-Fe-Au province,eastern China and is well endowed with Fe,Cu,and polymetallic skarn deposits.
文摘The Shiyaogou deposit,located in Songxian,Henan Province,China,is a medium-sized Molybdenum deposit newly discovered in the East Qinling molybdenum belt.Occurring in the altered Proterozoic Xionger Group,mineralization of the deposit consists of molybedenite disseminations and quartz -molybdenite veinlets and stockworks.Hydrothermal alteration is well developed and is composed of potassic alteration,silicification,sericitization,pyriti-
文摘The detailed geochemical research indicates that the tholeiitic basalts from Ganlongtang-Longba ophiolitic m（?）lange exhibit distinctive geochemical characteristics of high TiO<sub>2</sub> and low K<sub>2</sub>O,and depletion of light rare earth elements.They should be originated from a depleted asthenosphere mantle, belonging to ancient oceanic crust ophiolitic volcanic rock association.Compared with the Longba tholeiitic basalt,the Ganlongtang tholeiitic basalt shows
文摘Vast thickness gravel formation developed widely around Tibetan Plateau, it provides the evidences of the uplift strongly process of Tibetan Plateau and it is also the products of uplift. So the study on origin, sediment environment and deposit faces of gravel layers can reveal the process and feature of Tibetan Plateau. According texture and components and glue degree and lithostratigraphy context of gravels, these gravel layers were divided into lower Pleistocene Yumen gravel formation and Middle Pleistocene Jiuquan gravel formation by Prof. Sun Jianchu in 1942. Since then, a lot of works have been carried including magnetic chronology. However, the absolute accumulated age of gravel is not yet identical because of different methods and precision. In this paper, a 1000m thick Cenozoic sediment at Laojunmiao, located at the northern foothill of Qilian Mt., is dating for ESR systematically. 19 block samples were collected for ESR dating. The pretreated samples were irradiated with a 60 Co\|source in different dosage. The irradiated samples were kept untouched for about ten days and then measured with a JES\|FEIXG ESR spectrum with the following measurement conditions: room temperature, X\|band, Microwave power: 0 1mW and 2mW, modulation amplitude: 0 8mT, magnetic field scanning range (334±5)mT. We select Ge and E’ centre as the dating signal. The concentrations of radioactive elements, U, Th, K 2O, were determined by laser fluorescence, colorimetric spectrophotometry and atomic absorption techniques, respectively. AD value were obtained by linear regression. The results show that it is linear relationship between age and depth (thickness), and the age is well identical with paleomagnetic age.
文摘Recently the (U\|Th)/He method on apatite has been applied to studies of cooling and exhumation in mountain belts in order to place constraints on the low temperature cooling history (Wolf et al., 1997; House et al., 1998). Because the closure temperature of the method is 65～75℃, it provides useful information regarding the exhumation of rocks through the upper few kilometers of the earth’s crust. When the (U\|Th)/He method is coupled with methods such as 40 Ar/ 39 Ar with higher closure temperatures (210～500℃), a cooling history can be reconstructed over a wide range of temperatures. In eastern Nepal, in the Dudh Kosi valley a suite of samples from the Main Central Thrust (MCT) to the middle of the Higher Himalayan section was previously dated using 40 Ar/ 39 Ar on K\|feldspar, biotite, muscovite, and hornblende (Hubbard and Harrison,1989). We have applied the (U\|Th)/He method to apatite from these same samples. The structurally highest site, Ngozumba, is in the middle to upper part of the Higher Himalaya in the Gokyo valley. At Ngozumba previous 40 Ar/ 39 Ar ages include: muscovite at (16 6±0 4)Ma (closure temperature (CT)350℃), biotite at (16 8±1 4)Ma (CT 300℃), and K\|feldspar at (15 5±1 8)Ma (CT 250℃).The apatite age for an augen gneiss from this location was (6 3±3 8)Ma suggesting slower cooling for that part of the range during the last 15Ma. Structurally below Ngozumba, in the MCT zone, 40 Ar/ 39 Ar ages include:(20 9±0 2)Ma for hornblende (CT 500℃), (12 0±0 2)Ma for muscovite, and (8 0±0 2)Ma for K\|feldspar (CT 220℃). The apatite age obtained for a biotite schist at this location was (4 6±0 2)Ma and is consistent with relatively constant cooling since 12Ma. In between the MCT and the Ngozumba site samples were collected near the settlement of Ghat that yielded anomalously young 40 Ar/ 39 Ar ages:(7 7±0 4)Ma for muscovite, (7 5±0 6)Ma for biotite, and (3 6±0 2)Ma for K\|feldspar (CT 210℃). The apatite age is consistent with these young ages at (0 8±0 1)Ma. Plausible explanations for the young ages at this site include: post\|MCT age movement on a small\|scale shear zone or late\|stage movement of hydro\|thermal fluids through this localized zone. The MCT zone 40 Ar/ 39 Ar ages were used to constrain a one\|dimensional thermal model aimed at understanding rates of exhumation (Hubbard et al., 1991). The model yielded exhumation rates of 0 7～1 9km/Ma for the MCT zone region. The (U\|Th)/He age for apatite from this region is consistent with the model results. By coupling the (U\|Th)/He ages with the 40 Ar/ 39 Ar ages in this region we can determine that exhumation processes have acted at a relatively constant rate during the last 15～20 million years (with the possible exception of the Ghat location). Major fault activity likely pre\|dates this time period, or has had little affect on the cooling history.
文摘The journal Chemical Research in Chinese Universities is a comprehensive academic journal in the field of chemistry,published bimonthly since 1984.The journal publishes research articles,letters/communications and reviews written by faculty members,researchers and postgraduates in universities,colleges and research institutes all over China and overseas.It reports the latest and the most creative results of important fundamental research in all aspects of chemistry and of developments with significant consequences across sub-disciplines.This journal is sponsored by Jilin University and mandated by the Ministry of Education of P.R.China.
文摘The journal Chemical Research in Chinese Universities is a comprehensive academic journal in the field of chemistry,published bimonthly since 1984.The journal publishes research articles,letters/communications and reviews written by faculty members,researchers and postgraduates in universities,colleges and research institutes all over China and overseas.It reports the latest and the most creative results of important fundamental research in all aspects of chemistry and of developments with significant consequences across sub-disciplines.This journal is sponsored by Jilin University and mandated by the Ministry of Education of P.R.China.
文摘The journal Chemical Research in Chinese Universities is a comprehensive academic journal in the field of chemistry,published bimonthly since 1984.The journal publishes research articles,letters/communications and reviews written by faculty members,researchers and postgraduates in universities,colleges and research institutes all over China and overseas.It reports the latest and the most creative results of important fundamental research in all aspects of chemistry and of developments with significant consequences across sub-disciplines.This journal is sponsored by Jilin University and mandated by the Ministry of Education of P.R.China.
文摘A method for age dating of uranium mineral particles by double focusing magnetic sector inductively coupled mass spectrometry (FS-ICPMS) and thermal ionization mass spectrometry (TIMS) was presented. Pb/U ratio in uranium mineral particles was measured by FS-ICPMS without any chemical separation procedure. Pb isotope composition in uranium mineral particles was determined by TIMS associated with micro column anion exchange resin method. Due to simplified chemical procedure and minimum use of reagents, the full procedure blank was reduced to 230 pg Pb, leading to the successful age dating of uranium mineral particles with relative standard deviation less than 2%.
